First Print

Discussion in 'Getting Started' started by Spoon Unit, Aug 22, 2019.

  1. orcinus

    orcinus Well-Known Member

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    I put them on and remove them while debugging. Also, lack of stiffness might contribute to layer shifts, but not consistency of layer thickness / extrusion width, so doubt that would have any appreciable effect on what i’m ironing out.

    In case i wasn’t very clear earlier - my issue isn’t that the layers are shifted, or blobby, it’s that some layers are equally inset on all sides, or equally sticking out - i.e. extruded at different (volumetric) rates.

    The interesting thing is that if i fix that through adjustments to extruder acceleration and jerk, it’s fine for the tool/nozzle i was adjusting for, but then the other tool, with a different nozzle looks like crap.

    It’s almost as if i’d have to have gcode readjusting acceleration and jerk for every tool, on every tool change, which is doable, but slightly insane.
     
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  2. orcinus

    orcinus Well-Known Member

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    The infill isn’t meeting up with the perimeters. There’s very clear holes in it and it’s fairly rough. Discounting mechanical issues, this usually happens for one of the following reasons:

    - temp too low (viscosity)
    - particularly grainy or pastey filament (viscosity/adhesion)
    - x/y feedrate too high or too low for the extruder
    - extrusion width too high for the nozzle and/or chosen layer height

    My bet is on that last one, although it could just be the glittery filament.

    Your extrusion width should be equal to nozzle width as a starting point, then tweaked to accommodate for chosen layer height. Extrusion widths significantly greater than nozzle widths introduce nozzle drag marks, turbulence on the edges, and other artifacts. The higher your layer height and speed on top of that, the worse it gets (the farther away you get from laminar flow, the worse the die swell, etc.)
     
  3. Krayn

    Krayn Well-Known Member

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    Anecdotally my iPad pro (2018) tends to have one of the best WiFi antennas of any device I own. A device with a notoriously BAD antenna is my Nintendo Switch usually has one signal bar sitting next the toolchanger while the TC itself is working well. I'm sitting in a space between two Unifi APs. I'm not sure if there is a gcode I can send to get the signal strength, but Its at least better than a switch.

    For my first prints two weeks ago, I got a really old spool of white PETG, copied some settings from the github to prusaslicer, and got these:

    [​IMG]
    [​IMG]

    They aren't perfect but they are decent for having used the worlds stringiest filament. I live near the ocean so I believe my PETG spool is super wet. After retracting and moving from one side of the bed to the other I end up with about 2-3 cm of oozing out of the nozzle. I'm not drawing any conclusions yet, but its not bad given a fresh profile in prusaslicer with zero tuning.

    I spent the last two weeks using up all of my remaining old filament on some functional prints, including printing an enclosed filament holder I can mount on the extrusions and fill with some silica gel, and making sure all four tools are more or less working and aligned with the calibration print. I tested tool changing and using the non metallic wiper brush I found and it worked well but my PETG oozes waay too much for a multi material print. I'll be spending this week tuning the quality with new spools of various materials.
     
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  4. Spoon Unit

    Spoon Unit Well-Known Member

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    decent first print
     
  5. orcinus

    orcinus Well-Known Member

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    Ugh, yeah, Switch is pretty horrid.
    I usually don't use WiFi on it though, unless it's in a dock, updating, so i almost don't notice it. Almost.

    It's M122.
     
  6. orcinus

    orcinus Well-Known Member

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    Figured out where the underextrusion on top is coming from (by matching your setup).
    It's the linear advance.

    Default config (0.2) is pretty strong, and causes holes / needs more overlap between infill and perimeters.
     
  7. Spoon Unit

    Spoon Unit Well-Known Member

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    0.15mm print with 0,4 mm extrusion width. The obvious problem is due to accidentally leaving the PCF on. Shit happens.

    [​IMG]

    [​IMG]

    [​IMG]
     
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  8. orcinus

    orcinus Well-Known Member

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    Looks good!

    Odd that it's so matte with PCF off.
    Which filament was that?
     
  9. Spoon Unit

    Spoon Unit Well-Known Member

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    That's E3D Sky Blue PLA that they don't sell anymore. But actually, the PCF was on for the whole print, which is the reason for the warped base. This is less likely to happen now the the PCF can be properly controlled as a result of correct tool setup; it just needs to be defined in the slicer profile now.
     
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  10. orcinus

    orcinus Well-Known Member

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    Ah, i thought you had it *off* the whole time.
     
  11. orcinus

    orcinus Well-Known Member

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    Finally got it printing consistently.

    [​IMG]

    I've got no clue what the cause was, though.
    It went away after rebuilding the hotend and doing a cold-pull.

    Maybe the NozzleX had some residue in it out of the box?
    It doesn't take much to cause issues at 0.3mm.
     
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  12. Spoon Unit

    Spoon Unit Well-Known Member

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    The does look good.

    Print speed?
     
  13. orcinus

    orcinus Well-Known Member

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    I think it was around 40-50 perimeters, 80 loops, 70 infill.
    However, the issue is now back.

    It looks like something, somewhere, shakes itself loose (so to speak) after a certain amount of printing and it's back to the beginning.
    I've also nailed the problem down to occasional overextrusion. So it's not that the extrusion rate varies randomly from layer to layer - more like, periodically, when starting a new layer, it will spit out about double the regular amount of extrudate for no apparent reason. I caught it doing that by watching a whole print.

    I still think it might be the bowden coupler... More than once i've pulled on it while pushing the tube in, to minimize the amount of wiggle/slack, and then found it looser after a print, as if it slipped from the backpressure. I'll remove the PTFE tube completely and measure it, then replace it as my next troubleshooting step.
     
  14. Greg Holloway

    Greg Holloway Administrator
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    is the stepper motor / driver overheating?
     
  15. orcinus

    orcinus Well-Known Member

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    Nope.
    In fact, i've lowered the current from defaults so it's lukewarm.

    Anyways, i think i found the cause.
    It's a partial clog. Either PTFE cut wasn't clean enough (i did use a fresh, sharp xacto knife, but who knows) and a bit of it crumbled inside, or it had some residue out of the box. Either way - just did another overtemp PLA extrude at 260 deg C, then a cold pull at 100 C, and guess what - suddenly it's okay again.

    A partial clog would also explain the PTFE tube popping out - the pressure keeps building up until it "pops", then pressure goes down again, then builds up again etc. That's also probably why the overextrusion was highly periodic in nature.
     
  16. Greg Holloway

    Greg Holloway Administrator
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    hmmm interesting. hopefully you have fixed it now!
     
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  17. Spoon Unit

    Spoon Unit Well-Known Member

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    Meanwhile .... tuning in S3D, the purge, pre, post, firmware retraction and dump bucket ....

    0.2 layers

    [​IMG]
     
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  18. orcinus

    orcinus Well-Known Member

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    I suddenly have a craving for spaghetti and sauce.
     
  19. orcinus

    orcinus Well-Known Member

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    Fingers crossed.
    Proceeding with tuning flow rate and extruder non-linearity, hopefully now it keeps extruding fine.
     
  20. Spoon Unit

    Spoon Unit Well-Known Member

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    Will show him a flame and knife in the morning....

    I will say this little fella has really helped me settle on a solid purge system and I've developed some S3D script content and a Notepad++ macro to post process so that hopefully the next print is much better.

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]
     

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